This invention relates to an elevator hoist apparatus having a speed reduction gear mechanism composed of parallel axis gears and manufacturing method therefor.
FIGS. 5 and 6 are views schematically illustrating the elevator hoist apparatus disclosed in Japanese Patent Laid-Open No. 57-156986, in which reference numeral I designates a machine frame installed in the machine room and reference numeral 2 designates a gear box made of cast-iron mounted to the machine frame 1. Within the gear box 2, a speed reduction gear mechanism 3 composed of parallel axis gear as shown in FIG. 6 is disposed. Reference numeral 4 is an input shaft of the speed reduction gear mechanism 3, 5 is an intermediate shaft, 6 is an output shaft, these shafts being supported at their opposite ends by the gear box 2 by means of bearings 7. Reference numerals 8 designates a first gear mounted to the input shaft 4, which is in engagement with a second gear 9 mounted to the intermediate shaft 5. Reference numeral 10 designates a third gear mounted to the intermediate shaft 5, which is in engagement with a fourth gear 11 mounted to the output shaft 6. These gears 8-11 are helical gears. Reference numeral 12 designates an electric motor connected to the input shaft 4, 13 is a drive sheave connected to the output shaft 6, 14 is a main rope wound around the drive sheave 13, 15 is an elevator car connected to one end of the main rope 14 and 16 is a counter weight connected to the other end of the main rope 14.
In the elevator hoist apparatus of the above construction, when the electric motor 12 is rotated, its rotating force is transmitted to the output shaft 6 through the first to fourth gears 8-11 to rotate the drive sheave 13 which causes the car 15 to ascend or descend. Also, at that time, lubricating oil stored at the bottom of the gear box 2 is splashed up, whereby the lubrication of the gears 8-11 is achieved. During this operation, the force acting on the sheave 1 through the main rope 14 due to the weights of the car 15 and the counter weight 16, the force due to the driving force of the gears 8-11 by the motor 12, the force due to the weight of the motor 12 and the like are all supported by the gear box 2 made of the cast iron.
Since the conventional elevator hoist apparatus has the gears 8-11 supported by the gear box 2 as described above, the loads of the elevator car 15, the counter weight 16 and the like as well as the loads generated during the operation act against the gear box 2 through the bearings 7 for the gears 8-11 of the speed reduction gear mechanism 3, so that the gear box 2 must be extremely strong. Therefore, in the conventional elevator hoist apparatus, the gear box 2 made of cast iron is provided with a large wall-thickness, resulting in a very large weight of the entire hoist apparatus and in a difficulty in handling during the manufacture and assembly of the hoist apparatus and the installation of the hoist apparatus.
Also, since the shape of the gear box 2 is box-shape and is relatively complicated, casing is difficult and the accurate positioning of the bearing-receiving holes to be formed in a side wall 2 of the gear box 2 is difficult, which has been one of the factors that causes the gear meshing accuracy to be deteriorated. Furthermore, during the assembly of the hoist apparatus, the gears and the shafts must be inserted into and assembled within the closed space defined by the box-shaped gear box 2 manually, making the assembly difficult.